China is investigating possible stock-price manipulation amid the recent run-up in the country’s equity market, according to officials with direct knowledge of the matter, a move that serves as a reminder of the problems that have long haunted Chinese stocks.

The probe launched by the China Securities Regulatory Commission comes as stocks traded in mainland China rallied to their highest level in three years on Monday despite the country's weakening economic growth. Much of the surge, analysts and officials say, has been triggered by short-term speculators betting on looser monetary conditions as opposed to investors with a long-term belief in China's economy.